In conventional communication systems, information content such as video streams are transmitted to a set top box (STB) associated with a selected household. The video streams may be transmitted according to packetization defined by the Moving Pictures Experts Group (MPEG) standards. Additionally, messages related to the subject matter of the information content may be embedded in the packet identifier (PIDs) sections of the packets carrying the information content. Accordingly, these messages are transmitted as in-band data within the video streams. As used herein, the term “in-band data” means messages transmitted in packets as part of the information content and during the time period over which the information content is transmitted.
The predominant types of messages provided as in-band data are application-specific data and trigger information. Application-specific data typically includes application data and/or information for controlling the operation of the STB, while trigger information typically includes information regarding the time when the application data and/or the information received at the STB, should be launched. In interactive applications, the in-band data may be textual messages provided to the consumer to control the display of the interactive application. In STB-based advertisement insertions, the in-band data may be textual, audio and/or video advertisements, or commercials. Conventional STBs are limited in that they may receive in-band data only in association with the video stream that is being watched or recorded. Accordingly, the application data and/or information is limited to that which is closely related to the video content, thereby preventing delivery of application-data and/or information that is independent of the subject matter of the video content. Further, the STB cannot request in-band data associated with video streams other than the video streams that are contemporaneously being watched or recorded by the consumer. Finally, a STB may not be able to perform targeted advertisement insertion if the STB tunes to a communication band at a time when an advertisement break is in progress and/or if the advertisement insertion data has been missed.
Other disadvantages to providing messages as in-band data result from the bandwidth-intensive nature of the video content. Because video content is bandwidth-intensive, the bandwidth for in-band data transmission may be severely limited. Accordingly, application information, and corresponding bandwidth-intensive application features (i.e., rich graphics and multimedia content) that can be provided to a consumer, may also be severely limited.
Notwithstanding the aforementioned disadvantages, messages such as targeted advertisements may be distributed to STBs using quadrature amplitude modulation (QAM) channels. The STBs may include a tuner configured to tune to a specific channel when the STB receives instructions for such. However, transmitting targeted advertisements using QAM channels has numerous disadvantages. Dedicated QAM channels are typically employed for delivering targeted advertisements to a STB population. However, there are a finite number of QAM channels and limited bandwidth, for such purposes. For example, if the channels are using QAM256, then each QAM channel will have 38.8 megabits/second (Mbps) of bandwidth. Within this channel, programs are multiplexed into a multi-program transport stream, including different linear broadcast channels. A multiplex can carry up to 10 discrete programs or television streams, for MPEG-2 SD content if each program is 3.75 Mbps. Additionally, HD MPEG-2 programs will require up to 19 Mbps, if there is no rate-limiting protocols applied, and only two streams can be multiplexed. Because of the bandwidth limitations, and the fact that QAM channels are typically dedicated, the number of discrete advertisements that can be distributed to STBs over a selected time interval is small. Accordingly, STB granularity for transmitting targeted advertisements may be poor.